RAND() function returns a pseudo-random float value. This function can be called with argument or without argument. This argument refers to a seed value of the rand number. The seed value type may be any of these data types (tinyint, smallint or int).

The output value of rand() function is the range from 0 through 1 float value.

What is pseudo-Random number?

The random numbers used in computer programs are pseudo-random, which means they are generated in a predictable fashion using a mathematical formula. This is fine for many purposes, but it may not be random in the way you expect if you’re used to dice rolls and lottery drawings. – Random.org